For this sequence, recall from [1]} that we have the following pre-substitution on letters \([i],i\in \mathbb {N}\) .
\(\varrho ^{ }_{a}([0]) & =[0][1], \text{ and}\\\varrho ^{ }_{a}([i]) & =[0][i-1][i+1] \text{ for }i>0.\) 
